A 46-year-old woman with rheumatic heart disease, weighing 48 kg, had undergone a closed mitral valvulotomy for severe mitral stenosis many years before and recently presented with New York Heart Association class III symptoms. The patient gave written consent for this report. Preoperative transthoracic echocardiogram revealed severe restenosis of the mitral valve (MV), dilated tricuspid valve (TV) annulus with thickened and noncoapting leaflets, and severe tricuspid regurgitation (TR). The MV was replaced with a single tilting disk mechanical prosthesis (Chitra tilting disk valve, Chitra TTK, Chennai, India). The TV was repaired; however, the repair failed, and the valve was replaced with a 27-mm Chitra tilting disk mechanical prosthesis.
After surgery, 2-dimensional (2D) transesophageal echocardiography (TEE) and color flow Doppler (CFD) examination revealed a normally functioning MV prosthesis. The TV prosthesis initially was functioning well, but within a few minutes, intermittent incomplete disk closure with abnormal intraprosthetic regurgitation was seen on TEE (Figure 1A; Supplemental Digital Content 1, Video 1, http://links.lww.com/AA/B648). An echogenic structure suggestive of a tendinous chord was seen intermittently in the right atrium (RA) in systole and right ventricle (RV) in diastole (Figure 1, B and C; Supplemental Digital Content 1, Video 1, http://links.lww.com/AA/B648).
The patient was returned back on cardiopulmonary bypass (CPB), and a prolapsing chord near the anterolateral tricuspid annulus was excised. An attempt to wean the patient off CPB again resulted in abnormal intraprosthetic regurgitation. This time, the jet was imaged in each cycle with CFD and continuous-wave Doppler (Figure 2; Supplemental Digital Content 2, Video 2, http://links.lww.com/AA/B649). No obvious cause for the incomplete disk closure, however, could be identified with 2D TEE.
The heart was rearrested but no obstructing structures could be seen on surgical inspection of the RA. Suspecting a suboptimal orientation of the prosthesis, the surgeon rotated the disk by 180° so that the major orifice opened toward the interventricular septum (Figure 3). This resulted in resolution of the TR (Supplemental Digital Content 3, Video 3, http://links.lww.com/AA/B650). The postoperative course was complicated because of the prolonged CPB and subsequent RV dysfunction, but the patient eventually recovered.
The most common cause of TR is functional, secondary to left heart disease.1 Valve repair is the preferred technique, whereas replacement is reserved for those cases in which repair fails or is not feasible, such as organic TV disease.1 Important considerations for choosing the type of TV prosthesis (mechanical versus bioprosthetic) are long-term survival, reintervention rates for mechanical valve thrombosis, and degeneration of bioprosthetic prostheses.1 Mechanical TV prostheses are contraindicated if future pacemaker/defibrillator lead insertion is anticipated.2
Abnormal intraprosthetic regurgitation, mostly reported in mechanical MV prostheses, is caused by disk entrapment by preserved subvalvular structures (chordae tendinae, papillary muscles, leaflets) or debris, such as sutures,3–5 vegetations, or thrombus.2 Rarely, intraprosthetic TR may be functional due to incomplete disk closure resulting from a lower pressure differential between the RA and RV, in cases of elevated central venous pressures, depressed RV systolic function, or arrhythmias.
The cause of abnormal intraprosthetic regurgitation should be investigated by a combination of 2D, spectral, and CFD.6,7 Prolapsing chordae tendineae are visualized as thin filamentous structures on 2D TEE.3 Absence of acoustic shadowing differentiates them from valve struts.
In the Chitra single tilting disk valve, the position of the occluder disk creates 2 unequal orifices; the major orifice (below the RA struts) and the minor orifice (below the RV strut), which are visualized in multiple mid-esophageal views. Normal disk closure results in 2 small peripheral washing jets.
Abnormal intraprosthetic regurgitation, coinciding with the incomplete disk closure, is imaged in systole with CFD and has a dense early peaking waveform on continuous wave Doppler. In our case, improvement in RV pressures may have caused the tendinous chord to float freely and cause intermittent incomplete disk closure, which was not initially present while weaning off CPB.
Occasionally, subtle abnormalities in disk movement may not be detected with 2D TEE.5 In such cases, 3-dimensional (3D) TEE may have additional diagnostic value.5 Disk movement should always be assessed after complete separation from CPB because lower pressure differentials between the atria and ventricles may prevent complete closure.
Management of prosthetic valve dysfunction due to disk entrapment includes removal of the subvalvular obstruction and/or disk rotation within the valve housing. No recommendations exist for orientation of mechanical tilting disk tricuspid prosthesis, and in this case, the initial orientation was as per the surgeon’s preference.
To summarize, 2 different patterns of abnormal intraprosthetic TR were seen. In the first instance, intermittent regurgitation was due to a prolapsing chord. In the second instance, abnormal regurgitation was probably due to a faulty prosthesis orientation and occurred in all cycles. This case highlights the importance of 2D TEE in detecting prosthetic TV dysfunction and guiding management.
Clinician’s Key Teaching Points
By Massimiliano Meineri, MD, A. Stephane Lambert, MD, and Nikolaos J. Skubas, MD
- Malfunction of a newly implanted mechanical prosthetic valve may result in stenosis or regurgitation due to abnormal disk motion.
- In the mitral or tricuspid position, abnormal intraprosthetic regurgitation is caused by entrapment of residual valvular or subvalvular tissue, which may interfere with disk closure. Delayed or incomplete disk closure may also be functional if the transprosthetic pressure difference is low. With 2D and 3D TEE imaging, the disk motion can be assessed and the prosthetic function evaluated with CFD.
- In this patient with preoperative TR, a single, tilting disk mechanical TV prosthesis was inserted. After separation from CPB, significant, intermittent intraprosthetic regurgitation was noticed in the mid-esophageal 4-chamber view. An independently mobile tendinous structure was seen prolapsing into the RA in systole, causing incomplete disk closure. After surgical resection of the tricuspid subvalvular apparatus, TR was present in each cardiac cycle, most likely from interference of the myocardial wall with the disk. Surgical rotation of the prosthesis finally resulted in normal prosthetic function.
- Intraprosthetic regurgitation must be promptly identified after separation from CPB. Normal backflow, or “washing jets,” is of low velocity, occurs with normal disk motion, and varies with the type of prosthesis. Abnormal intraprosthetic flow has high velocity and is due to incomplete disk closure. The size, location, timing, and duration of the regurgitant jet may provide clues to the underlying mechanism.
Name: Satyajeet Misra, MD, DNB, PDCC, TEE Certified (EACVI).
Contribution: This author helped design and prepare the manuscript.
Name: Vivek V Pillai, MS, MCh.
Contribution: This author helped prepare the manuscript.
Name: Bineesh K Radhakrishnan, MS, MCh.
Contribution: This author helped prepare the manuscript.
This manuscript was handled by: Nikolaos J. Skubas, MD, DSc.
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